CDK-111A-Lite Owner's Guide - Ross Video

2. Write CommandsWrite commands are used by the editor for operations that configure thekeyer or update its parameters, such as adjusting the setting of an analogcontrol or starting an auto transition.The keyer responds to a write command by returning a two-byte statusmessage. The first byte count is set to 01H. The second contains the keyerresponse to the command. The format of this second byte is as shownbelow.BitBit7 6 5 4 3 2 1 00 00 00Logic Zero (undefined)1=Key Loss Blanking (*)1=Communication Error (*)1=RX Buffer Warning1=Protocol Error1=Command Accepted*= if enabledWrite Command – Format of Second ByteIf bit 6 or bit 7 is high, the meaning is as follows:• Protocol Error – If bit 6 is high (logical “1”), an illegal function may havebeen specified.• Command Accepted – If bit 7 is high (logical “1”), then the command hasbeen accepted.• Rx Buffer Warning – High when the receive buffer is very close to full andin danger of dropping messages. (Not currently implemented)• Communication Error bit – High if a communication error has occurred sincethe last break command while placing characters in the command queue.(Not currently implemented)• Key Loss Blanking – Set when an on-air key is not displayed on the PGMoutput because a key signal (alpha or fill or background) is missing or bad.(Not currently implemented)4-8 • Appendix A. Serial Protocols CDK-111A-Lite • Owner’s Guide v4B